Azaleas are hardy perennial shrubs that come in two basic species, evergreen azaleas (Rhododendron tsutsusi) and deciduous azaleas (R. pentanthera). The deciduous azaleas bloom in springtime with either bright yellow, orange, pink or magenta flowers. Azaleas grow best in USDA hardiness zones 4 or 5 through 9, where winter temperatures stay above minus 25 to minus 15 degrees Fahrenheit. If you plant azaleas that are either native to or are appropriate for your region's climate, you'll have little to do in caring for the azaleas in winter.
Spread a 4- to 5-inch layer of leaf or bark mulch on the ground around your azaleas in the fall, before the first frost. The mulch will help to insulate the azaleas' shallow roots from freezing temperatures.
Reduce any regular watering of the azaleas during the autumn. Stop watering the plants in the fall and throughout the winter.
Stop fertilizing the azaleas by August to allow them to harden off for the winter. Don't start feeding the azaleas again until mid-spring.
Prune away any broken growth damaged by frosts, freezes or snow cover. Prune the azalea to remove this damaged growth in spring after the new growth emerges. You can prune the azaleas again right after the blooms fade.